为自己加油

Choose the closest paraphrased version for each of the sentences or italicized parts.

This, I think, is the proper recipe for remaining young.（）

A.
This is the best thing to do to keep fit.
B.
This is the right way to stay young.
C.
This is the healthy food one should eat in old age.
D.
This is the secret of maintaining a youthful appearance.